The present application relates to systems and methods for reducing vibrations in photovoltaic panel arrays. For example, and without limitation, the disclosed subject matter includes photovoltaic panel arrays designed to rotate in order to track the movement of the sun.
Solar energy can be converted to electric energy through the use of photovoltaic panels (“PV”s). One or more PVs can be attached to a rotating structure forming an array configured to follow the sun. The array of PVs can rotate over the course of the day to maintain alignment with the sun, and thus energy production can be increased. Such an array can include a motor driving a rotating beam to which the PVs are attached. The beam can have a length suitable to exhibit torsional properties. In operation, the surface area of the PVs can be urged due to force from wind and thus can apply torsion forces to the rotating beam. Varying wind speeds (e.g., wind buffeting) can induce a harmonic vibration in the rotating structure, which can increase loads on the array.
Dampers from other applications have been used to reduce the vibrations induced by wind buffeting. Such dampers can provide a large damping force at low input velocity and maintain, or only slightly increase, this damping force as input velocity increases. This is known as digressive damping. Digressive damping works well in certain applications, such as automotive applications, at least in part because the high damping force at low input velocity prevents an automobile from bobbing while still allowing the springs to absorb the forces of high velocity impacts, such as those created by hitting a pothole. Digressive damping can be unsuitable, however, for PV applications, at least in part because wind buffeting can induce high velocity vibrations in the PV array, and larger damping forces are required to counteract these high velocity vibrations.
Another type of damping, called progressive damping, can also be used. Progressive damping is designed to increase damping force as input velocity increases. In operation, however, as wind buffeting introduces high velocity vibrations, correspondingly high damping forces exerted by a progressive damper can exceed the structural strength of the PV array, which can cause a structural failure of the PV array.
As such, there is an opportunity for an improved PV array damping assembly that can provide progressive damping to reduce vibrations in the PV array induced by wind buffeting without exceeding the structural strength of the PV array.